Alternating current light-emitting device and fabrication method thereof

ABSTRACT

An alternating current light-emitting device includes a substrate, a plurality of microdie light-emitting elements formed on the substrate, a rectifying element-dedicated member formed on a surface of a portion of microdie light-emitting elements, a rectifying unit formed on the rectifying element-dedicated member and provided with at least four rectifying elements forming a Wheatstone bridge circuit, and an electrically conductive structure electrically connecting the rectifying elements and the microdie light-emitting elements. With the rectifying unit being formed on the rectifying element-dedicated member, the rectifying elements are highly tolerant of reverse bias and feature low starting forward bias. Also, the present invention provides a method for fabricating an alternating current light-emitting device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending application Ser. No.11/710,564, filed on Feb. 26, 2007, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120. This application also claims priority under 35 U.S.C.§119(a) on Patent Application No. 095141256 filed in Taiwan on Nov. 8,2006, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to light-emitting devices, and moreparticularly, to an alternating current light-emitting device and afabrication method thereof.

2. Description of the Prior Art

With continual advances in optoelectronic technology, light emittingdiodes (LED), a kind of light sources, are in wide use and of vitalimportance to optoelectronic industry. In an AC-dominant livingenvironment, conventional DC-driven LED chips can function well only inthe presence of an external AC-to-DC converter circuit and a voltagedrop element, thus resulting in high costs and unsatisfactoryperformance. This problem calls for development of AC-operated LEDchips. AC-operated LED chips (AC LED) have been put forth bymanufacturers based in the United States, Japan, South Korea and Chinasince 2005, indicating that AC LED is deemed a novel component of greatpotential.

U.S. Pat. Nos. 6,547,249 and 6,957,899 and Taiwanese Patent ApplicationNo. 093126201 disclose a single chip having a plurality of miniaturizedlight-emitting diode dies connected to one another such that the chip isdirectly operated in a high-voltage AC environment, and the disclosuresshare features as follows: at least one AC microdie LED module formed ona chip, wherein the AC microdie LED module at least comprises two LEDmicrodies electrically connected to one another, and under an appliedalternating current the microdies emit light in turn in accordance withthe way of circuit connection. Although the LED microdies function verywell in an AC environment, each of the LED microdies emits light duringhalf of a cycle. This means a waste of light-emitting area, as only halfof the microdies are operating at a forward bias at every single instantin an AC environment.

To overcome the aforesaid drawback, a design of AC LED with anequivalent circuit like Wheaston's bridge was put forth, which involvesdisposing a light-emitting microdie module in a region of constantdirection of rectified current to allow the light-emitting microdie toemit light whether the AC bias is forward or reverse. However, thedesign brought about another problem: LEDs have poor tolerance to areverse bias, and thus rectification can only be achieved by LEDs when alarge number of LEDs are used, which also results in a waste of microdiesurface area.

Accordingly, the aforesaid drawbacks of the prior art call for immediatesolution for directly fabricating on the surface of a LED die arectifying element highly tolerant of reverse bias and characterized bylow starting forward bias.

SUMMARY OF THE INVENTION

In light of the aforesaid drawbacks of the prior art, it is a primaryobjective of the present invention to disclose an alternating currentlight-emitting device with enhanced tolerance to a reverse bias and afabrication method thereof.

Another objective of the present invention is to disclose an alternatingcurrent light-emitting device with enhanced unit area utilization and afabrication method thereof.

Yet another objective of the present invention is to disclose analternating current light-emitting device with a Wheatstone bridgecircuit and a fabrication method thereof.

In order to achieve the above and other objectives, the presentinvention discloses an alternating current light-emitting device atleast comprising: a substrate; a plurality of microdie light-emittingelements formed on the substrate, each of the microdie light-emittingelements at least being provided with an active layer and anelectrically conductive terminal; a rectifying element-dedicated memberformed on a surface of a portion of the microdie light-emittingelements; a rectifying unit formed on the rectifying element-dedicatedmember, provided with at least four rectifying elements forming aWheatstone bridge circuit, and adapted to provide rectification andoutput a direct current signal to each of the microdie light-emittingelements; and an electrically conductive structure for electricallyconnecting the rectifying elements and the microdie light-emittingelements.

As regards the alternating current light-emitting device, the substrateis a chip or an insulated substrate, and the active layer is alight-emitting activity layer. The electrically conductive terminal ofeach of the microdie light-emitting elements is an Ohmic electrode. Therectifying element-dedicated member is a rectifying element-dedicatedlayer formed by epitaxy or deposition. The rectifying element-dedicatedlayer is preferably a semiconductor material AlGaN. The rectifyingelement-dedicated member is a rectifying element-dedicated region formedby doping a dopant into the substrate. The dopant is preferably ann-type dopant, and the rectifying element-dedicated region is formed byion implantation or diffusion.

In a preferred embodiment, the microdie light-emitting elements aredisposed in a matrix and connected in series, in parallel, or bothaccording to the requirement for monochromatic light or light mixing.The microdie light-emitting elements emit light at identical ordifferent wavelengths. The number of the microdie light-emittingelements used varies as appropriate, so as to vary the result of lightmixing. In another preferred embodiment, each of the microdielight-emitting elements comprises a buffer layer, an n-typesemiconductor, an active layer, and a p-type semiconductor. Theelectrically conductive structure is an electrically conductive bridge,a metallic wire-bonding structure, or a transparent metal oxide layercapable of electrical conduction. The rectifying element is a Schottkydiode.

To achieve the aforesaid objectives, the present invention furtherdiscloses two methods for fabricating the alternating currentlight-emitting device.

The first fabrication method at least comprises the steps of: providinga substrate; forming on the substrate a plurality of microdielight-emitting elements at least provided with one active layer; formingon a surface of a portion of the microdie light-emitting elements arectifying element-dedicated layer; forming on the rectifyingelement-dedicated layer a rectifying unit provided with at least fourrectifying elements forming a Wheatstone bridge circuit; forming agroove for insulating the microdie light-emitting elements and therectifying elements from one another; forming an electrically conductiveterminal on each of the microdie light-emitting elements; and forming anelectrically conductive structure for electrically connecting therectifying elements and the electrically conductive terminals of themicrodie light-emitting elements.

The first fabrication method further comprises the steps of definingregions of the rectifying elements on a surface of the rectifyingelement-dedicated layer by etching before forming the rectifying unit,and removing a residual portion of the rectifying element-dedicatedlayer thoroughly. The first fabrication method further comprises thesteps of enclosing a periphery of the microdie light-emitting elementswith a protective layer, and removing a portion of the protective layerso as to form the plurality of electrically conductive terminalspenetrating the protective layer, wherein the protective layer is madeof a dielectric material, such as SiO_(x) and SiN_(x).

The second fabrication method at least comprises the steps of: providinga substrate; forming on the substrate a plurality of microdielight-emitting elements at least provided with one active layer; dopinga dopant into a surface of a portion of the microdie light-emittingelements to form a rectifying element-dedicated region by decreasingdoping concentration; forming on the rectifying element-dedicated regiona rectifying unit provided with at least four rectifying elementsforming a Wheatstone bridge circuit; forming a groove by etching so asto insulate the microdie light-emitting elements and the rectifyingelements from one another; forming an electrically conductive terminalon each of the microdie light-emitting elements; and forming anelectrically conductive structure for electrically connecting therectifying elements and the electrically conductive terminals of themicrodie light-emitting elements. The second fabrication method furthercomprises the step of defining regions of the rectifying elements on therectifying element-dedicated region by etching before forming therectifying unit.

The method for fabricating the alternating current light-emitting deviceof the present invention comprises forming the rectifying unit on therectifying element-dedicated member, wherein the rectifyingelement-dedicated member is formed on the substrate by epitaxy,deposition, diffusion, or implantation. Therefore, the rectifyingelements are characterized by high tolerance to reverse bias and lowstarting forward bias, thereby reducing the number of the rectifyingelements of the rectifying unit, providing more room for an increasednumber of microdie light-emitting elements, increasing unit areautilization, and enhancing light emission efficiency. Accordingly, thepresent invention overcomes a drawback of the prior art, that is, poortolerance of conventional light-emitting microdies to reverse bias and alarge number of light-emitting microdies required for rectification.

The embodiments below merely serve as the preferred embodiments of thepresent invention. The embodiments below should not be construed as tolimit the scope of the present invention in any way. Hence, any otherchanges can actually be made in the present invention. It will beapparent to those skilled in the art that equivalent modifications orchanges can be made to the present invention without departing from thespirit and the technical concepts disclosed by the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are side views showing structure of a rectifyingelement-dedicated layer above an active layer of an alternating currentlight-emitting device in accordance with the present invention;

FIGS. 2A and 2B are side views showing die structure of microdielight-emitting elements of an alternating current light-emitting devicein accordance with the present invention;

FIGS. 3A and 3B are schematic views showing an equivalent circuit of analternating current light-emitting device in accordance with the presentinvention; and

FIGS. 4A and 4B are top plan views schematically showing a layout ofcomponents of an alternating current light-emitting device in accordancewith the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following specific embodiments are provided to illustrate thepresent invention. Persons skilled in the art can readily gain aninsight into other advantages and features of the present inventionbased on the contents disclosed in this specification.

The present invention discloses an alternating current light-emittingdevice applicable to a substrate, for example, a chip. The alternatingcurrent light-emitting device is provided with a monochromatic ornon-monochromatic light source by means of microdie light-emittingelements driven under an applied AC power rectified by, for example, aWheatstone bridge circuit. The monochromatic or non-monochromatic lightsource is disposed on a light exit surface of the chip and is capable offull-time light emission. The alternating current is preferably theelectricity supplied to the general public at voltages of 100V, 110V or220V, and frequencies of 50 Hz or 60 Hz.

Referring to FIGS. 1A to 4B, which are schematic views showingembodiments of an alternating current light-emitting device and afabrication method thereof in accordance with the present invention.

The present invention provides an alternating current light-emittingdevice at least comprising: a substrate 16; a plurality of microdielight-emitting elements 20 a, 20 b and 20 d formed on the substrate 16,each of the microdie light-emitting elements 20 a, 20 b and 20 d atleast being provided with an active layer 13 and an electricallyconductive terminal; a rectifying element-dedicated member, for examplea rectifying element-dedicated layer 15 or a rectifyingelement-dedicated region 17, formed on a surface of a portion of themicrodie light-emitting elements, for example the microdielight-emitting element 20 d; a rectifying unit formed on the rectifyingelement-dedicated member and including at least four rectifying elements203 a electrically connected in a Wheatstone bridge circuit to provide arectification function and output direct current (DC) signals to themicrodie light-emitting elements 20 a and 20 b; and electricallyconductive structures 23 a and 23 b selected from the group consistingof an electrically conductive bridge, a metallic wire-bonding structure,and a transparent metal oxide layer capable of electrical conduction andadapted to electrically connect the rectifying elements 203 a and themicrodie light-emitting elements 20 a and 20 b.

The substrate 16 can be a chip or an insulated substrate. The activelayer 13 can be a light-emitting activity layer. The electricallyconductive terminals of the microdie light-emitting elements 20 a and 20b are Ohmic electrodes 201 a, 201 b, 202 a, and 202 b. The rectifyingelement-dedicated member is a rectifying element-dedicated layer 15(FIG. 1A) made of semiconductive material such as AlGaN by epitaxy ordeposition. The rectifying element-dedicated member can also be arectifying element-dedicated region 17 (FIG. 1B) obtained by doping adopant, preferably an n-type dopant, into the surface of a portion ofthe microdie light-emitting elements, for example the microdielight-emitting element 20 d, by ion implantation or diffusion.

Referring to FIG. 1A, which shows an epitaxial structure of a microdielight-emitting element of an alternating current light-emitting devicein accordance with the present invention, a microdie light-emittingelement is made from a chip 10 by epitaxy (though a fabrication methoddisclosed in the present invention is not limited to epitaxy), theepitaxial structure of the chip 10 at least comprises a substrate 16, abuffer layer 11 formed on the substrate 16, an n-type semiconductor 12on the buffer layer 11, an active layer 13 on the n-type semiconductor12, a p-type semiconductor 14 on the active layer 13, and a rectifyingelement-dedicated layer 15 on the p-type semiconductor 14. Taking a GaNgroup semiconductor as an example, the rectifying element-dedicatedlayer 15 is preferably implemented by intrinsic semiconductor AlGaN orany similar semiconductor. The main purpose of the rectifyingelement-dedicated layer 15 is to provide material required forfabrication of the rectifying elements of the rectifying unit (notshown) such that the rectifying elements are characterized by highbreakdown reverse bias and low starting forward bias.

Preferably, the substrate 16 is implemented by semiconductor materials,such as Al₂O₃, GaAs, GaP and SiC, and any insulated materials.

FIG. 1B depicts the structure of another microdie light-emitting elementof an alternating current light-emitting device. Unlike what isillustrated with FIG. 1A, in FIG. 1B, a dopant is doped into adiode-based epitaxial surface of the chip 10 by ion implantation ordiffusion to reduce the doping concentration thereof. Taking the GaNepitaxy in wide use as an example, although a GaN chip surface istypically p-doped, the present invention discloses doping a n-typedopant, such as Si, into a p-type GaN film by ion implantation ordiffusion, and then, upon activation, the doping effect of the p-typeand n-type dopants offsets one another to such an extent that the dopantconcentration in the rectifying element-dedicated region 17 of thesurface of the chip 10 decreases to approximately the dopantconcentration of an intrinsic semiconductor, which is conducive tofabrication of a rectifying element (not shown).

FIG. 2A is an exploded view showing the structure of neighboringmicrodie light-emitting elements of an alternating currentlight-emitting device 20 comprising microdie light-emitting elements 20a, 20 b and 20 d. The microdie light-emitting elements 20 a and 20 beach include at least one active layer 13. The active layer 13 is alight-emitting active layer. As shown in FIG. 2A, the surface of themicrodie light-emitting elements 20 a and 20 b is not provided with therectifying element-dedicated layer 15. The active layers 13 of themicrodie light-emitting elements 20 a and 20 b are each provided withOhmic electrodes 201 a, 201 b, 202 a, and 202 b. Alternating currentapplied to the Ohmic electrodes 201 a, 201 b, 202 a, and 202 b allowsthe active layers 13 to emit light.

A rectifying element 203 a shown in FIG. 2A is formed on the surface ofthe microdie light-emitting element 20 d, wherein the microdielight-emitting element 20 d comprises at least one active layer 13. Therectifying element-dedicated layer 15 is disposed above the activelayers 13 and configured for fabrication of electrodes related to therectifying element 203 a. The structure is fabricated by epitaxy,deposition, diffusion, or implantation. The rectifying element 203 a isa Schottky rectifying electrode. Applying a forward bias to therectifying element 203 a in the direction of an Ohmic electrode 203 bdecreases potential barrier at a metal-semiconductor junction andtherefore current passes the junction. Conversely, applying a forwardbias to the Ohmic electrode 203 b in the direction of the rectifyingelement 203 a increases potential barrier at a metal-semiconductorjunction and therefore current does not pass the junction. In doing so,rectification is achieved.

Electrically conductive structures 23 a and 23 b of FIG. 2A allowelectrical connection to be formed between the microdie light-emittingelements 20 a and 20 b and the rectifying element 203 a. Theelectrically conductive terminals of a microdie light-emitting element20 a comprises the Ohmic electrodes 201 a and 201 b connected to theOhmic electrodes 202 a and 202 b of another microdie light-emittingelement 20 b through the electrically conductive structure 23 a. Theelectrical connection between the microdie light-emitting elements 20 aand 20 b and the rectifying element 203 a is formed by means of theelectrically conductive structure 23 b. The electrically conductivestructures 23 a and 23 b are preferably an electrically conductivebridge.

FIG. 2B is a schematic view showing another embodiment of the presentinvention. Unlike what are shown in FIG. 2A, FIG. 2B shows a singlemicrodie with functions of rectification and light emission. The singlemicrodie of FIG. 2B includes a complete structure of a microdielight-emitting element 20 d, and the rectifying element-dedicated layer15 and the rectifying element 203 a formed thereon. The rectifyingelement 203 a is a Schottky rectifying electrode and is formed on therectifying element-dedicated layer 15. The Ohmic electrode 203 b isformed on the n-type semiconductor 12 below the rectifying element 203a. In the presence of a forward bias, current passes the active layer 13of the microdie light-emitting element 20 d and enables the active layer13 to emit light. In the presence of a reverse bias, the rectifyingelement 203 a stops the passage of current and therefore achievesrectification. This embodiment achieves maximum light-emitting area bymeans of the simplest fabrication process.

FIG. 3A is a schematic view showing an equivalent circuit of analternating current light-emitting device equipped with rectifyingelements. As shown in FIG. 3A, rectifying elements 31 a, 31 b, 31 c and31 d are equivalent to the aforesaid rectifying elements 203 a and areelectrically connected to one another in a Wheatstone bridge circuit toform a rectifying unit 31. Alternating current inputted to an AClight-emitting module is rectified by the rectifying element 31 a of therectifying unit 31 before being inputted to a microdie light-emittingmodule 32 a (including an appropriate amount of microdie light-emittingelements, like the microdie light-emitting element 20 a), and then thealternating current is rectified by the rectifying element 31 d, therebyallowing the microdie light-emitting module 32 a to emit light under aconstant forward bias. Likewise, alternating current rectified by therectifying element 31 c is inputted to the microdie light-emittingmodule 32 a and then rectified by the rectifying element 31 b, therebyallowing the microdie light-emitting module 32 a to emit light under aconstant reverse bias.

The way of electrical connection of the microdie light-emitting elements(for example, the microdie light-emitting elements 20 a and 20 b of FIG.2A) of the microdie light-emitting module 32 a shown in FIG. 3A is notlimited to single-row series connection. For instance, the microdielight-emitting module 32 b of the circuit schematically shown in FIG. 3Bfeatures double-row parallel/series connection. The microdielight-emitting module 32 b of the present invention comprisesmonochromatic or multichromatic microdie light-emitting elementsconnected in series or in parallel; in other words, light mixing can bevaried by selectively using an appropriate amount of microdielight-emitting elements emitting light of identical or differentwavelengths.

Referring to FIG. 4A, which is a top plan view schematically showing anembodiment of an alternating current light-emitting device equipped witha Wheatstone Bridge circuit in accordance with the present invention,the alternating current light-emitting device comprises the rectifyingelements 41 a, 41 b, 41 c, and 41 d, and, under different bias voltages,alternating current passes wire bonding electrodes 43 and 44 beforeentering the Wheatstone bridge circuit and then the microdielight-emitting elements 42. Doing so allows the microdie light-emittingelements 42 disposed in a matrix to stay at a constant forward biasoperating condition so as to increase die surface utilization. As shownin FIG. 4A, the rectifying elements 41 a, 41 b, 41 c, and 41 d aredisposed below the wire bonding electrodes 43 and 44, and thuspreviously unusable regions become capable of rectification. As aresult, the light-emitting area of the alternating currentlight-emitting device (applicable to what is shown in FIG. 2A)increases.

FIG. 4B illustrates another embodiment of the present invention. Unlikethe embodiment shown in FIG. 4A, the embodiment of FIG. 4B is based on acombination of the rectifying elements 41 a, 41 b, 41 c, and 41 d andthe microdie light-emitting elements 42, which allows the rectifyingelements 41 a, 41 b, 41 c, and 41 d to emit light, and the rectifyingelements 41 a, 41 b, 41 c, and 41 d emit light in the way as theremaining microdie light-emitting elements 42 do when connected to thewire bonding electrodes 43 and 44 and electrically conductive. As aresult, the light-emitting area of the alternating currentlight-emitting device (applicable to what is shown in FIG. 2B)increases.

The present invention further discloses two methods for fabricating thealternating current light-emitting device. Related to FIG. 1A, the firstfabrication method comprises: providing a substrate 16, forming on thesubstrate 16 the microdie light-emitting elements 20 a, 20 b and 20 dhaving at least one active layer 13 by epitaxy, forming on a surface ofthe microdie light-emitting elements 20 a, 20 b and 20 d a rectifyingelement-dedicated layer 15 by epitaxy or deposition; defining regions ofthe microdie light-emitting elements 20 a, 20 b and 20 d on the diesurface by etching, forming on the rectifying element-dedicated layer 15a rectifying unit having at least four rectifying elements 203 a forminga Wheatstone bridge circuit; removing the rectifying element-dedicatedlayer 15 from the surface of the microdie light-emitting elements 20 aand 20 b thoroughly; forming a groove by dry etching or wet etching soas to insulate the microdie light-emitting elements 20 a, 20 b and 20 dfrom one another; enclosing a periphery of the microdie light-emittingelements 20 a, 20 b and 20 d with a protective layer, removing a portionof the protective layer so as to form the plurality of electricallyconductive terminals penetrating the protective layer; allowing theelectrically conductive terminals beneath the protective layer to formwith the plurality of electrically conductive structures 23 a and 23 bfor electrically connecting the rectifying elements 203 a and themicrodie light-emitting elements 20 a and 20 b with a view to formingthe rectifying elements 203 a of the Wheatstone Bridge circuit, whereina DC signal is outputted to the rectification-oriented electricalconnection formed by the plurality of microdie light-emitting elements20 a and 20 b, thereby allowing light emission to take place.

Related to FIG. 1B, the second fabrication method comprises: providing asubstrate 16, forming on the substrate 16 the microdie light-emittingelements 20 a, 20 b and 20 d having at least one active layer 13 byepitaxy, forming on a surface of the microdie light-emitting elements 20a, 20 b and 20 d a rectifying element-dedicated region 17 by doping adopant into the surface of a portion of the microdie light-emittingelements 20 a, 20 b and 20 d by ion implantation or diffusion anddecreasing the doping concentration thereof; forming on the rectifyingelement-dedicated region 17 a rectifying unit having at least fourrectifying elements 203 a forming a Wheatstone bridge circuit; forming agroove by dry etching or wet etching so as to insulate the microdielight-emitting elements 20 a, 20 b and 20 d from one another; enclosinga periphery of the microdie light-emitting elements 20 a, 20 b and 20 dwith a protective layer, removing a portion of the protective layer soas to form the plurality of electrically conductive terminalspenetrating the protective layer; allowing the electrically conductiveterminals beneath the protective layer to form with the plurality ofelectrically conductive structures 23 a and 23 b for electricallyconnecting the rectifying elements 203 a and the microdie light-emittingelements 20 a and 20 b with a view to forming the rectifying elements203 a of the Wheatstone Bridge circuit, wherein a DC signal is outputtedto the rectification-oriented electrical connection formed by theplurality of microdie light-emitting elements 20 a and 20 b, therebyallowing light emission to take place.

The electrically conductive structures 23 a and 23 b referred to in thetwo methods for fabricating the alternating current light-emittingdevice of the present invention are selected from the group consistingof an electrically conductive bridge, a metallic wire-bonding structure,and a transparent metal oxide layer capable of electrical conduction.

The protective layer referred to in the two methods for fabricating thealternating current light-emitting device of the present invention ismade of a dielectric material, such as SiO_(x) and SiN_(x).

The electrically conductive terminal referred to in the two methods forfabricating the alternating current light-emitting device of the presentinvention is formed by vapor deposition.

The method for fabricating the alternating current light-emitting deviceof the present invention comprises forming the rectifying unit on therectifying element-dedicated member, wherein the rectifyingelement-dedicated member is formed on the substrate by epitaxy,deposition, diffusion, or implantation. Therefore, the rectifyingelements are characterized by high tolerance to a reverse bias and a lowstarting forward bias, thereby reducing the number of the rectifyingelements of the rectifying unit, providing more room for an increasednumber of microdie light-emitting elements, increasing unit areautilization, and enhancing light emission efficiency. Accordingly, thepresent invention overcomes a drawback of the prior art, that is, poortolerance of conventional light-emitting microdies to a reverse bias anda large number of light-emitting microdies required for rectification.

The aforesaid embodiments merely serve as the preferred embodiments ofthe present invention. The aforesaid embodiments should not be construedas to limit the scope of the present invention in any way. Hence, anyother changes can actually be made in the present invention. It will beapparent to those skilled in the art that all equivalent modificationsor changes made to the present invention, without departing from thespirit and the technical concepts disclosed by the present invention,should fall within the scope of the appended claims.

What is claimed is:
 1. A method for fabricating light-emitting device,comprising the steps of providing a substrate; forming a first typesemiconductor layer on the substrate; forming an active layer on thefirst type semiconductor layer; forming a second type semiconductorlayer on the active layer; forming a plurality of microdielight-emitting elements comprising the first type semiconductor layer,the active layer, and the second semiconductor layer; forming aplurality of rectifying elements comprising the first type semiconductorlayer, the active layer, the second type semiconductor layer, and arectifying element-dedicated member, wherein the rectifyingelement-dedicated member is formed on or in the second typesemiconductor layer; and forming an electrically conductive structurefor electrically connecting the rectifying elements and the microdielight-emitting elements.
 2. The method for fabricating a light-emittingdevice of claim 1, further comprising the steps of enclosing a peripheryof the microdie light-emitting elements with a protective layer,removing a portion of the protective layer, and forming a plurality ofelectrically conductive terminals penetrating the protective layer. 3.The method for fabricating a light-emitting device of claim 2, whereinthe protective layer comprises a dielectric material.
 4. The method forfabricating a light-emitting device of claim 2, wherein at least one ofthe electrically conductive terminals is an ohmic electrode.
 5. Themethod for fabricating a light-emitting device of claim 1, wherein eachof the rectifying elements comprises a Schottky electrode.
 6. The methodfor fabricating a light-emitting device of claim 1, further comprisingthe step of forming a groove, wherein the groove is formed to insulatethe microdie light-emitting elements from one another.
 7. The method forfabricating a light-emitting device of claim 6, wherein the groove isformed by dry etching or wet etching.
 8. The method for fabricating alight-emitting device of claim 1, wherein the microdie light-emittingelements are formed by epitaxy.
 9. The method for fabricating alight-emitting device of claim 1, wherein the electrically conductiveterminals are formed by vapor deposition.
 10. The method for fabricatinga light-emitting device of claim 1, wherein the substrate is a chip. 11.The method for fabricating a light-emitting device of claim 1, whereinthe electrically conductive structure is a metallic wire-bondingstructure.
 12. The method for fabricating a light-emitting device ofclaim 1, wherein the electrically conductive structure is a transparentmetal oxide layer.
 13. The method for fabricating a light-emittingdevice of claim 1, wherein the step of forming the microdielight-emitting elements on the substrate further comprises forming abuffer layer between the substrate and the first type semiconductorlayer.
 14. The method for fabricating a light-emitting device of claim1, further comprising the step of forming the plurality of microdielight-emitting elements on the substrate in a matrix.
 15. The method forfabricating a light-emitting device of claim 14, wherein the pluralityof the rectifying elements are disposed outside of the matrix.
 16. Themethod for fabricating a light-emitting device of claim 1, furthercomprising the step of connecting the rectifying elements into aWheatstone bridge circuit.